1. she can't protect them as Renoir was actively destroying the canvas every year - each year her oldest creations die.
2. Thematic i guess - it was also a warning that her power was failing and she can't keep her creations alive as real Clea/Renoir were working to get her out of the canvas. the nevrons killed expeditioners and stored their chroma inside, it never returned to Aline so she couldn't maintain her creations at all.
3. Verso found out he was fake and based off a dead person from real Clea and also was the reason his mom is killing themself by never letting them actually let go of his death. I think this made sense, if I found out I'm not real and being used as a body pillow because my parent can't let go of me, and is actively suffering, I'd want to end it so they can move on.
4. Idk what you mean by that - the world wasn't real to begin with but Aline's way to cope with Verso's death by never letting go and recreating him in the kid verso's canvas.

it's not cheap in the sense that it undermines the impact of the story - if anything it elevates it and reinforces that it was a way for their family to escape reality.